I have a '67 327 motor which broke the #8 cylinder exhaust spring. The intake, header, and head bolts have been removed but the heads are not separating from the engine. Any thoughts on how to remove them? Am I missing any hiden bolts? (removed 17 bolts per head).

 

as far as i know is that you have 17 bolts holding the head on. only thing me and my brother can think of is the alignment dowel pins. they could just be stuck together from being together for so many years.

 

No hidden bolts, as long as you got all of them off. It's just stuck in place. Try a putty knife between the head and block and pry up. If that doesn't give, use a thin screwdriver. You don't want to go gouging way in between the head and block and hurt the sealing surfaces. Just pop it up as close to the outer edge as possible.

 

Sometimes they stick pretty good because of the gasket,a little tap with a big hammer and a block of wood might do it if the puttyknife doesn't get it.
That said why are you pulling the head just to change a valve spring? bent valve too?